Art of combustion and steam generation



Aug. 5, 1930. v z. CARACRISTI ART OF COMBUSTION AND STEAM GENERATION Filed March 6, 1925 2 Sheets-Sheet 1 Aug. 5, 1930. RA I 1,772,276

ART OF COMBUSTION AND STEAM GENERATION Filed March 6, 1925 2 Sheets-Sheet 2 IN VEN TOR WQ M A TTORNE Y5 Patented Aug. 5, 1930 other objects as may UNITED STATES PATENT I OFFICE VIBGINIUS Z. OABACRISTI, OI BRONXVILLE, NEW YORK, ASSIGNOB TO LOOOMOTIVE PULVEBIZED FUEL COMPANY, A CORPORATION 01 DELAWARE ART OF COMBUSTION AND STEAM GENERATION Application filed March 8, 1925. Serial 110. 13,502.

plication Serial No. 695,969 filed February 'This invention relates generally to improvements in the art of combustlon and of generating steam, and, while capable of other applicationsflt is especially useful in furnaces and boilers in which the fuel is burned in a finely divided state as, for example, in the form of pulverized coal. v

One of the primary objects of the 1nvention is to increase the capacity of the boiler thereby making it possible to generate more steam-from a boiler of given size or by way of increasing the capacity of existing boilers.

Another object of the invention is to protect the refractories; and-this without interference with either the fuel admission or the combustion of the fuel.

A more limited object of the invention 1s to locate evaporating surfaces under the arches or in the outlet throat of combustion chambers.

How the foregoing, together with such e are incident to my invention, is rea ized, is

illustrated in the accompanying drawings,'

in which Fig. 1 is a fragmenta vertical section thru one form of boiler. an furnace embodyimprovements;

' in my Fig. 2 is a section taken on the line. 2-2,

of Fig. 1

Fig. 3 illustratesfa modification of the in vention;

Figs. 4:, 5 and 6 are sections taken on the lines, 4.-4, 55, and 66,'respectively, of

ig. 3; i

Fig. 7 is an elevation of Fig. 3; and Figs. 8 and 9, illustrate still other modifications.

In the embodiment shown in Figs. 1 and 2, the furnace is fired from each of two opposite sides and the boiler consists of two groups of inclined tubes oppositely disposed so that the products of combustion rise upwardly therebetween and, by suitable baffling, are passed thr'u each group to the stack.

The products of combustion, of course, divide approximately half being baflied thru one group of tubes and the remainder thru the other group. This general arrangement is now not new, it being disclosed in-my apreinafter ap ear or tion is supplied thru horizontal compart having a central ofltake 7 in the upper part thereof, fuel being introduced in a downward direction at each of two opposite sides, thru the roof or arch 8 by means of burners 9, arranged in a row and constructed in accordance with any desired design. The fuel from each row of burners descends downwardly, becomes ignited and the fuel and flame continues downwardl mentum is overcome by the raft whereupon it bends and ascends in the manner indicated.

This is described and claimed in the afore said application. f

The fuel is led to the burners, preferably with carrying air, by the ipes 10. Addltional combustion air is a mitted thru the burner-casings.

The balance of the air required for combusbecomes heated, promoting efliciency. Y

The oil'take 7 is formedby a throat 14 o substantial dimensions. At about theupward end of the throat proper, the lower drums 15 of the holler are carried, only one such drum being shown, it being understood, of course,

that a corresponding drum is located. at the opposite side of the throat. From each drum 15 banks of tubes 16 extend to u per drums. Only one such group is shown. or purposes of illustration. 1

- In order to prevent the accumulation of the refuse deposited in the lower portion of the combustlon chamber in the form of molten slag, I arrange two water screens 17 and 18 above the bottom of the. combustion chamber until its mo- I such screens comprising a plurality of suitably spaced tubes between which the precipitatlng particles pass and by which they are accumulated below slag forming temperature. The tubes of the screen 17 are connected at the lower end to a header19 and the tubes ofthe screen 18 have their lower ends connected to a similar header 20, such headers in turn being connected by downcomers 21, of suitable size, to the drums 15. The upper ends of the tubes of the screens 17 and 18 are connected into the headers 22, such headers in turn being connected by suitable upcomers 23 to headers 24. The headers 22, the upcomers 23 and the headers 24 may be, and preferably are, located exterior of the combustion chamber. The headers 24 are located in a plane just below the arch 8. Extending inwardly from the headers 24 are tubes 25 which are arranged with reference to the arch and the throat in the manner indicated in the figure. The upper ends of these tubes 25 are connected into, the drums 15 and such tubes constitute upcomers.

The tubes 25v are spaced as illustrated in Fig. "2 and have their upper portions 25 forked, that is, the portions adjacent the walls of the throat 14, thus providing more tubes in the throat. This further provides adequate space 26 between the tubes 25 at their lower ends, thru which the stream of fuel and air delivered by each burner may pass into the combustion chamber. The tubes 25 are very largely subjected to radiant heat, not only 35 .from the combustion chamber proper, but also from the throat wherein combustion takes place to approximately the level indicated under well conducted operating conditions.

By virtue of this, such tubes absorb a very large quantity of heat and add very greatly to the capacity of the boiler, as do the screens 17 and 18. The tubes 25 also function to protect the arch and the throat so that the refractory material of which they are composed, has long life.

It will be observed that this is all done without interference with the admission of the coal and may also be accomplished without unduly retarding or interfering with combustion, for the reason that the fuel and flame stream is subjected on at least four sides to radiant heat from the refractories, in addi tion to which heat is introduced into the combustion space with the air which is preheated in the hollow upright walls.

Altho each screen, together with its respective set of tubes 25, is connected into the circulation of the boiler, they have, in a sense, local circulation/ It will be appreciated from what has gone before that the capacity of the boiler is very substantially increased indeed and this without increasing the size of the installation, con- 65 sidered as a whole.

It will be noted that very little, if any, of the products of combustion comes into contact or close proximity to the tubes 25, the products of combination, as well as any flame in the throat, having a straight rise.

This invention has been described in connection with a powdered coal burning furnace, but it is to be understood as applicable to the protection of arches and throats of furnaces burning other kinds of fuel, and also to other types of boilers. Thus, for example, in Figs. 8 and 9 I have shown two other types of boilers equipped with suitable furnace settings. The tubes 25, as before, cover the arch and the throat. In the one case, the tubes connect with a steam and water drum 28 and with a header 24 in turn connected to the mud drum 26 by a large tube or tubes 27; and in the other case with a boiler header 29 and with a header 24 connected, as before, with the water screen, but having other connection 30 to a header 31, connected by a plurality of tubes 32 to the steam and water drum 33.

In both instances, the tubes may be bifurcated, or may be not, as in the arrangement of Fig. 3 now to be described. Here the arch 8 is composed of bricks supported, for example, from the beams 34 as shown in Fig. 5. The throat is composed of bricks 35 supported, for example, as shown in' Fig. 6 from castings 36 hun from the structural work. The burner nozz es 37 are flattened and project between the tubes 25 which are not bifurcated. The tubes 25, in this case, connect with a header 24 and with tubes 38 of the boiler, passing through the drum 15. Downcomers 39 from the drum suppl the header 24, 4O representing a blow 0 connection. The tubes 25 have plates 41 welded thereto for carrying the bricks 42, as shown in Fig. 3. The bricks radiate heat, but do not wear rapidly because of the protection afforded by the tubes.

I claim:

1. In combination, a combustion chamber, evaporating elements having branched and unbranched portions arranged therein, and means for introducing fuel in the space between the unbranched portions of the tubes. 115

2. In combination, a combustion chamber having an arch providing an offtake throat,

a boiler subject to the flow of gaseous products through the throat, a row comprising a plurality of relatively closely spaced tubes 120 connected into the circulation of the boiler and extending over the inner face of the arch and subject to radiant heat, and means for firing finely divided fuel through the said arch and row of tubes.

3. In combination, a boiler having upper and lower drums, and-connecting bank of tubes, a combustion chamber, an arch below the lower drum forming part of said combustion chamber, a row of tubes extending 130 over the inner face of the arch having their upper ends connected to deliver to said boiler, header means outside the chamber for the other ends of said tubes and downcomer means from said lower drum to said header means also located outside the chamber.

4. In combination, a combustion chamber having an arch providing a throat along the chamber proper, a boiler subject to the gaseous products of combustion passing through said throat, a row of inclined spaced tubes within the lower part of the chamber and exposed to radiant heat, header means outside the chamber for the upper ends of said tubes, a row comprising a plurality of relatively closely spaced tubes extendin over the inner face of said arch having t e upper ends arranged to deliver to the boiler, header means outside of the chamber for the other ends of said arch tubes, risers connecting said two header means, and down'comer means for su plying the lower ends of the said inclined tu es.

In testimony whereof, I have signed my name.

VIRGINIUS Z. CARACRISTI.

hereunto 

